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Zn1−xCuxO nanoparticles were synthesized by using sol–gel method. Structure and optical properties of Zn1−xCuxO nanoparticles were studied experimentally and theoretically. The simulations are based upon the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. The results showed that the UV emission is effectively quenched and the emission in visible-light region is enhanced by Cu-doping, which are theoretically explained to be attributed to the electronic intra-band transition from the occupied bands to the unoccupied ones under irradiation. Therefore, Zn1−xCuxO system may be a potential candidate for photocatalytic in visible light range.

Zn0.86Cd0.11In0.03O alloy semiconductor film was deposited on quartz substrate by pulsed laser deposition technique. Cd is used to change the optical band gap and In is used to increase the carrier concentration of the ZnO film. XRD studies confirm that the structure of Zn0.86Cd0.11In0.03O is hexagonal wurtzite structure without CdO phase appeared. FE-SEM shows that the grain size of Zn0.86Cd0.11In0.03O film is smaller than that of ZnO. These films are highly transparent (∼85%) in visible region. Most importantly, the electrical properties of Zn0.86Cd0.11In0.03O film highly improved with In doped. It has low resistivity (4.42×10−3 Ω cm) and high carrier concentration (5.50×1019 cm−3) that enable this film a promising candidate for window layer in solar cells and other possible optoelectronic applications.

The ignition temperature of the thermal explosion reaction from the Ti-C system under air is much lower than that under Ar atmosphere. The ignition mechanism for the Ti-C system under air is determined to be a mechanism of chemical oven, and the reaction mechanism is dissolution, reaction, and precipitation. Namely, the heat generated from the oxidation and nitrification of Ti and C can promote the melting of Ti inside the compact; subsequently, the carbon atoms dissolve into the Ti melt and TiC precipitate.

The products of combustion synthesis reaction in Ti–Si system with molar ratios of Ti:Si = 3:1, 5:3, 5:4, 1:1, and 1:2 were investigated. The phase composition of products and degree of completion in the reaction considerably depend on the initial stoichiometric ratios of reactants. During the SHS reaction of Ti–Si system, the degree of completion follows the order of 5Ti + 3Si > Ti + Si > Ti + 2Si > 5Ti + 4Si > 3Ti + Si. Besides, the micro-structural morphology of Ti–Si compounds, i.e., TiSi2, TiSi, Ti5Si4, and Ti5Si3 were also characterized in this study.

Al90Ni2.5Ti2.5La2.5Mn2.5 alloy with multicomponent alloying elements was prepared by rapid solidification. The hardness and the compression strength of the alloy reached 285 HV and 712 Mpa, respectively. The alloy exhibited good wear resistance, which was three times that of the conventional A309 aluminum alloy. The high strength and wear resistance of the alloy were attributed to the second-phase strengthening and the solid solution strengthening mechanisms.

The effect of the reactant particle size on the self-propagating high-temperature synthesis (SHS) reaction behaviors in the Ni-Ti-B4C system was investigated in the present study. The B4C particle size has a significant effect on the ignition behavior and combustion wave velocity, while Ti and Ni particle sizes have only a limited influence. Increasing the B4C particle size retards the reaction initiation and remarkably lowers the combustion velocity and combustion temperature. The reaction products are mainly dependent on the B4C particle size. Nevertheless, decreasing Ni and Ti particle sizes is in favor of perfect products consisting of only TiC, TiB2, and Ni phases.

The SHS reaction in the Ni–Ti–B4C system starts with the formation of Ni–Ti and Ni–B intermetallic compounds from the solid interacted reaction among the reactants and, subsequently, the formation of Ni–Ti and Ni–B liquid at the eutectic point. Meanwhile, some C atoms from the reaction between Ni and B4C can dissolve into Ni–Ti liquid to form TiC. The heat generated from these reactions can promote the mutual diffusion of Ni–Ti–C and Ni–B liquid and simultaneously accelerate the formation of Ni–Ti–C–B liquid. Finally the precipitation of TiC and TiB2 occur when the C and B atoms in the liquid become supersaturated. The addition of Ni not only promotes the occurrence of the self-propagating high temperature synthesis (SHS) reaction by forming Ni–Ti liquid, but also accelerates the SHS reaction by forming Ni–B liquid and dissociative C. The early appearance of dissociative C from the reaction between Ni and B4C causes the formation of TiC prior to that of TiB2.

The effect of melt superheating treatment on the microstructure of Mg–1.5Si–1Zn alloy is investigated in this article. The microstructure of samples poured into sand and metal molds shows that the primary Mg2Si is considerably refined in size when the melt is superheated from 750 to 900 °C. However, its polyhedral morphology does not change. In addition, also the size of eutectic Mg2Si phase obviously decreases, but the morphology still exhibits Chinese script type. Meanwhile, it is concluded that the reduction of the heredity plays an important role in the grain refinement of Mg–1.5Si–1Zn alloy.

In the present study, Al–Si alloys with Si contents of 23, 26, 28 and 31 wt.%, respectively, were modified with a new modifying agent. The results show that the primary silicon size decreased about 8–10 times after modification. The wear rates of the modified and heat-treated Al–Si alloys are lower than those of the unmodified and non-heat-treated Al–Si alloys, respectively. The silicon content in the range of 23–31 wt.% has a significant effect on the wear rates of the same processed Al–Si alloys (modification and heat treatment). Under the same load, the wear rates of the same processed Al–Si alloys decreased with the increasing silicon content. The abrasion took place mainly by cutting and partly by ploughing actions for the non-heat-treated Al–Si alloys, or on the contrary, mainly by ploughing and partly by cutting actions for heat-treated Al–Si alloys.

Exothermic reaction path of the Ni–Ti–B4C system in the differential thermal analysis apparatus proceeded in such a way that Ni initially reacted with B4C and Ti to form Ni–B compounds and Ti2Ni with heat release, respectively; subsequently, the formation of Ni–B eutectic liquid between Ni2B and Ni4B3, and the appearance of Ni–Ti eutectic liquid phase between Ti2Ni and Ti were followed, which enabled the diffusion of Ni, B, C, and Ti in solution to form Ni–Ti–B–C liquid more easily and quickly at a low temperature; finally, TiC and TiB2 were precipitated out of the liquid. The addition of Ni provided an easier route for reactant mass transfer and accelerated the occurrence of complete reaction.

The AZ91 metal matrix composites (MMCs) reinforced with 5, 10 and 15 wt.% TiC particulates are fabricated by TiCp–Al master alloy process combined with mechanical stirring. The effects of TiC particulate content, applied load and wearing time on the sliding wear behaviors of the composites were investigated using MM-200 wear testing apparatus. The results show that the wear resistance and friction coefficient of the composites increased and decreased with increase of the TiC particulate content, respectively. The wear volume loss and friction coefficient of the reinforced composites as well as the unreinforced AZ91 matrix alloy increased with increase of applied load or wearing time, but the increase rates of the reinforced composites in two performance is lower than those of the unreinforced AZ91 matrix alloy. Furthermore, the sliding wear behavior of the composites and the unreinforced AZ91 matrix alloy is characterized by ploughing, adhesion and oxidation abrasion.

The effect of La2O3 addition on the microstructure of partially remelted Mg-9Al-1Zn (AZ91D) alloy was studied. The results indicate that small amounts of La2O3 additions to AZ91D alloy refined the partially remelted microstructure and caused the formation of new phase- LaAl4 in the microstructure. Moreover, the grain size of the partially remelted alloys is decreased with the increasing of La2O3 addition. In as-cast microstructure the LaAl4 phases have two morphologies: needle-like and particle-shape. The presence of more LaAl4 phases, especially, the particle-shape LaAl4 which dispersedly distributed within the grains can induce more dislocations, which can result in the occurring of a large amount of recrystallizations. Moreover, these LaAl4 phases can also restrain the growth and combination of the recrystallizations and partially remelted initial grains during the subsequent heat-treatment.

Magnesium MMCs reinforced with TiB2−TiC particulates were fabricated successfully via a master alloy route using a low cost Al-Ti-B4C system as starting material system. Microstructural characterization of the (TiB2−TiC)/AZ91 composite shows relatively uniform distribution of TiB2 and TiC particulates in the matrix material. Moreover, the results show that the hardness and wear resistance of the composites are higher than those of the unreinforced AZ91 alloy.

The effect of different manufacturing techniques on the shape memory effect (SME) of the Fe14Mn6Si9Cr5Ni alloy has been studied. The SMEs of casting and forged alloys are similar. At ambient temperature, creep and stress-relaxation experiments of the casting alloy show that the casting alloy presents a good creep rupture strength. The manufactured pipe joints of the casting alloys keep jointing under a tensile force of 20 kN and keep sealing under a pressure of 5 MPa. Those excellent mechanical properties satisfy the requirements for pipe jointing in general industrial applications.

The stacking-fault energy (γsf) of iron-based shape-memory alloys was calculated by the extended dislocation-node method. The results show that Ni and Mn increase the γsf of the alloys with an austenite structure, while Cr and Si decrease it. An expression relating the alloying elements of Ni, Cr, Mn, and Si to the γsf of the alloys is established. Moreover, in terms of the γsf values of the alloys and the Schaeffler diagram, the alloy design of iron-based shape-memory alloys is carried out. It is found that the alloy having the lowest γsf has the best shape-memory effect (SME), with a martensite transition temperature (Ms) being a little lower than ambient temperature. The corresponding composition of the alloy is located in the γ-phase zone near the phase line between the γ and γ+e phase zone and the triple point of α+γ+e in the Schaeffler diagram.

Based on a newly developed size-dependent cohesive energy formula for two-dimensional materials, a unified theoretical model was established to illustrate the gap openings in disordered graphene flakes, involving quantum dots, nanoribbons and nanoporous sheets. It tells us that the openings are essentially dominated by the variation in cohesive energy of C atoms, associated to the edge physicochemical nature regarding the coordination imperfection or the chemical bonding. In contrast to those ideal flakes, consequently, the gaps can be opened monotonously for disordered flakes on changing their sizes, affected by the dimension, geometric shape and the edge saturation. Using the density functional theory, accordingly, the electronic structures of disordered flakes differ to the ideal case because of the edge disorder. Our theoretical predictions have been validated by available experimental results, and provide us a distinct way for the quantitative modulation of bandgap in graphene for nanoelectronics.

Using a powder hot-pressing technique, a high-strength Al-8Mn-2Ce alloy (atomic percent (at.%)) in a size of φ20 × 10 mm has been made. The parameters used to obtain the highest strength of 895 MPa for the alloys are a pressing temperature of 803 K, a pressing time of 15 min, and a pressing stress of 1.2 GPa.

Takagi was the first to demonstrate that ultrafine metallic particles melt below their corresponding bulk melting temperature in 1954 [1]. Now it is known that the melting temperatures of all nanocrystals, including metals [2, 3], semiconductors [4, 5] and organic nanocrystals [6, 7], depend on their size and this has been explained in terms of various models related to interface energy [8]. This size effect is experimentally also observed on the melting enthalpy [2, 6]. However, none of the above models can interpret sizedependent melting enthalpy of nanocrystals directly [8]. Knowledge of thermodynamic parameter are important for complete understanding of melting transition of nanocrystals and will deepen our insight into the size effect on melting. Therefore, a direct consideration on the size-dependence of melting enthalpy is needed. In this contribution, a simple physical model for the size-dependent melting enthalpy of nanocrystals in terms of the effect of bond number and bond energy of surface atoms of nanocrystals and that of the corresponding liquids on the internal energy of the system is developed. Combining with Mott’s expression for the vibrational entropy of melting for metallic crystals, size-dependent melting temperature of metallic nanocrystals is also predicted. The model predictions correspond well to the latest experimental results of indium nanocrystals. We consider that size-dependent melting enthalpy H (r ) is additive where r denotes radius of nanoparticles and nanowires, or half thickness of thin films

A model for the size dependence of the Curie temperature Tc of perovskite ferroelectric particles without any free adjustable parameters has been developed. The model predicts that Tc decreases with decreasing particle size. The predictions of the model are in agreement with experimental results for PbTiO3 and BaTiO3.

Failure analysis of the hermetical AISI 304L stainless steel cladding in oxidative chlorination reactor shows that its pitting and stress corrosion arose due to the presence of chlorine ion in the working environment. In order to improve its corrosion resistance, AISI 316L stainless steel should be utilized.